export const getDistance = (lat1: number, lon1: number, lat2: number, lon2: number) => {
    const R = 6371; // 地球半径（公里）
    const dLat = (lat2 - lat1) * Math.PI / 180;
    const dLon = (lon2 - lon1) * Math.PI / 180;
    const a =
        Math.sin(dLat / 2) * Math.sin(dLat / 2) +
        Math.cos(lat1 * Math.PI / 180) *
        Math.cos(lat2 * Math.PI / 180) *
        Math.sin(dLon / 2) * Math.sin(dLon / 2);
    const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
    return (R * c).toFixed(2); // 返回距离（公里）
}
